Until two weeks ago New Zealand's casualties in 10 years in Afghanistan had been remarkably light.

OPINION:
Some of that may be attributed to the bulk of New Zealand's deployment having involved troops doing reconstruction work in Bamiyan province, an area regarded as relatively safe, at least as far as anywhere in Afghanistan may be regarded as safe.

Some of our deployment, however, has included elite Special Air Service units who have become engaged in extremely hazardous encounters with Afghan guerrillas. That only five of our soldiers had until last week been killed may owe something to luck but much more to the high degree of professionalism with which they have operated.

The low casualty rate has meant that questioning of New Zealand's role in Afghanistan has until now been subdued. The loss of five more soldiers in the space of the last fortnight has changed all that. In a society as small and close-knit as New Zealand's, casualties in war have a disproportionate impact and after the latest deaths more voices are calling for an early withdrawal from the war, questioning whether we should have entered it at all and asking whether the results are worth the losses.

Eroding political support for military action is, of course, one of the main aims of a guerrilla war and is clearly the aim of the Taleban. While foreign forces remain in the country, the occasional skirmishes, suicide-bomb attacks and roadside bombs that the Taleban have been using would not be enough to win the war. With such attacks the Taleban can, however, hope to diminish support for the war among foreign governments and so hasten their withdrawal.

Some countries that went into Afghanistan in 2002 have already withdrawn. New Zealand, along with the United States and other countries, has for some time been planning to withdraw. For logistical reasons and because the withdrawal has to be co-ordinated with allied troops, the precise timing has been uncertain, although the Government earlier this year said New Zealand's forces would be out of Afghanistan completely in 2013.

Any alteration to that timetable would not only be difficult it would also smack of what the Prime Minister, John Key, has called cut and run. That would not only be contrary to the great care with which decisions on New Zealand's deployments have been taken by both Labour and National governments, it would also dishonour the sacrifices made by those who have served in those deployments.

As instability and violence continue it is inevitable to wonder whether the losses and expenditure have been worthwhile. New Zealand entered Afghanistan, along with more than 40 other nations, to get rid of a government that was offering a haven to al Qaeda terrorists and to kill or capture the terrorists.

Few doubted then, nor can it reasonably be doubted now, that invasion was the only way to deal with the problem. After al Qaeda was routed it was also necessary that considerable effort had to be made to rebuild the government and reconstruct the country.

Large gains have been made but little more is likely to be achieved by staying longer. A peaceable, democratic nation has not been created, but that was never going to happen. The Taleban may return but if it does it will return to a vastly different country, one that will not be able to become a haven for threats to the rest of the world. That goal has been worth achieving.